"It is precisely because I am in the habit of using my senses to think of things that I find it difficult to think of anything else."

"I confess that I have never been able to find out what is the 'substantial form' of a human body, or how it differs from the form of a statue."

"I am accustomed to sleep, and in my dreams to imagine the same things that lunatics do when awake."

"For it is not enough to have a good mind, but rather it is necessary to apply it well."

"The senses deceive from time to time, and it is prudent never to trust wholly those who have deceived us even once."